IndexThe chemical and its sourcesMedically known as trimethylxanthineEffects of caffeine on humansHealth benefitsCaffeine is a naturally occurring alkaloid found in the leaves, seeds and fruits of more than 63 plant species worldwide. It is an alkaloid of the methylxanthine family. Methylxanthines caffeine (1,3,7-trimethylxanthine), theobromine (3,7-dimethylxanthine) and theophylline (1,3-dimethylxanthine) are usually found in tea leaves, kola nuts, coffee beans, broad beans of cocoa, in mate leaves and other types of plants. Although coffee and tea drinks naturally contain caffeine and other methylxanthines, caffeine is an ingredient in many carbonated soft drinks, including colas, pepper drinks, and citrus drinks. Pure caffeine comes in the form of fluffy, odorless, white masses, glittering needles of powder. Its molecular weight is 194.19 g, the melting point is 236°C, the point at which caffeine sublimates is 178°C at atmospheric pressure, the pH is 6.9 (1% solution), the weight specific is 1.2, volatility is 0.5%, vapor pressure is 760 mmHg at 178°C, solubility in water is 2.17%, vapor density 6.7. Caffeine has attracted more attention in recent decades due to its physiological effects as well as its stimulant effect. The Food and Drug Administration (FDA) defines caffeine as a substance generally recognized as safe (GRAS). However, the FDA specifies that the maximum amount in carbonated beverages is limited to 0.02% (FDA 2006). Therefore, the maximum legal amount of caffeine allowed in a 355 ml (12 ounce) can of soft drink is approximately 71 mg. Caffeine has attracted the interest of consumers and healthcare professionals due to its widespread consumption in the diet of a large percentage of the population and its pharmacological effects on humans (Mandel 2002). The level of caffeine in human saliva, which demonstrates the extent of absorption, peaks approximately 40 minutes after caffeine consumption (Liguori et al 1997). Its physiological effects on many body systems have been informed by researchers, including the central nervous, cardiovascular, gastrointestinal, respiratory, and renal systems (Nehliget al 1992). The International Olympic Committee (IOC) has defined caffeine as a drug and abuse is indicated when athletes have urine caffeine concentrations above 12 µg/mL. Say no to plagiarism. Get a tailor-made essay on "Why Violent Video Games Shouldn't Be Banned"? Get an original essay Caffeine is a central nervous system stimulant. It is one of the most popular drugs in the world, consumed by approximately 90% of the world's people in one form or another, but mostly in drinks. It is a natural substance found in plants such as cocoa beans, tea leaves and kola nuts. Caffeine's strongest effects are felt about an hour after ingestion, but some effects last 4 to 6 hours. Caffeine causes an increase in the activation of neurons in the brain, which the pituitary gland perceives as an emergency and therefore causes the adrenal glands to release adrenaline. Caffeine also increases levels of dopamine, the neurotransmitter that is affected by drugs such as amphetamines and heroin. Obviously, it does so at a much lower level than these drugs, but this may be the source of caffeine's addictive quality. The Chemical and Its Sources Today, caffeine is believed to be “the most widely used psychoactive drug in the world.” Some studies estimate that 90% or more of this country's population uses caffeine, whether through foods, beverages, or prescription and over-the-counter medications. The most common sources of caffeine for Americans include brewed coffee, brewed tea, and typical beveragesof cola, milk and dark chocolate and over-the-counter drugs such as "Anacin" and "Vivarin". Caffeine is an alkaloid, or nitrogen-containing substance, with the chemical formula C8H10N4O2. It belongs to the family of chemicals known as methylxanthines, which also includes the closely related chemicals theophylline and theobromine. In its pure form, caffeine “appears as odorless, white, fluffy masses, glittering needles or powder. Like all methylxanthines, caffeine has low solubility and is therefore often combined with a wide variety of compounds to form complexes, such as double-salt sodium benzoate, for specific purposes. Medically known as trimethylxanthines, caffeine and other methylxanthines occur naturally “in plants” and are widely distributed geographically.”12 Tea, which is prepared from the leaves of the Theasunensis plant, naturally contains all three of the above-mentioned methylxanthines. and is consumed by at least half of the entire world population.13 Cocoa and chocolate are produced “from the seeds of Theobroma cacao”; both contain caffeine and theobromine, and both are used throughout the world.14 The most obvious and important source of American caffeine intake, coffee, is produced from the Coffea arabica plant.15 Before the deliberate inclusion of additional caffeine during production , many carbonated soft drinks contain a natural form of caffeine "due to their Cola acuminata nut extract content." caffeinated beverage consumed most frequently. The caffeine contained in coffee is a bioactive compound with stimulating effects on the central nervous system and a positive effect on long-term memory. Although coffee consumption has historically been linked to negative health effects, new research indicates that coffee consumption may be beneficial. Here we discuss the impact of coffee and caffeine on health and bring attention to the evolving caffeine landscape that includes new energy drinks and caffeinated supplements, often aimed at children and adolescents. Caffeine has numerous physiological effects on major organ systems, including the nervous system. , cardiovascular system, digestive system and respiratory system. Kidney function and skeletal muscles are also affected by caffeine. Numerous studies have shown that caffeine is a stimulant of the human central nervous system (Spiller, 1998). It also increases the heart rate, dilates blood vessels and increases the levels of free fatty acids and glucose in the plasma. 1 g of caffeine causes insomnia, nervousness, nausea, ringing in the ears, piercing flashes of light and tremors. In case of overdose and in combination with alcohol, narcotics and other drugs, these compounds produce a toxic effect, sometimes with lethal outcome (Mamina and Pershin, 2002; Ben Yuhas, 2002; Manyika et al., 2010; James et al., 1990; Tavallali and Sheikhaei, 2009). Caffeine facilitates the speed of conduction in the heart and directly affects the contractility of the heart and blood vessels. However, caffeine can significantly reduce cerebral blood flow by narrowing cerebral blood vessels. Caffeine provides a diuretic effect due to increased blood flow and glomerular filtration rate of the kidneys. Heartburn is a problem for the gastrointestinal system of some people after consuming caffeine. The effects of caffeine on skeletal muscles are mainly the increasing occurrence of tremors. Health BenefitsIn Japan, researchers have shown that caffeine increases memory. Additionally, a more recent study from Johns Hopkins University showed that a 200 mg caffeine pill helped boost memory consolidation. Caffeine may protect against Parkinson's disease. There.